The invention relates to apparatus for cutting sheet material into any of a wide variety of polygon shapes. The invention is particularly useful for cutting pieces of insulation for use to line duct work transition pieces. The cutting apparatus of the invention can be designed to be semi-automatic or fully automatic. Semi-automatic operation is desirable, and according to the invention, a single operator may quickly and easily cut out a wide variety of shapes of sheet material with minimum effort.
According to the present invention, the sheet material cutting apparatus includes a first elongated support member with a first cutting tool mounted on the first support member for movement therealong. A sheet material support surface is provided with first and second guide members disposed on opposite sides of the support surface. Means are provided for pivotally mounting the first support member, for pivotal movement about a generally vertical axis, with respect to each of the first and second guide members, means are provided for providing linear movement of the pivotal mounting means with respect to the first and second guide members, along the first and second guide members, and means are provided for providing linear relative movement between the support member and the pivotal mounting means. The first and second guide members are spaced a predetermined distance apart and disposed in the same generally horizontal plane. Means are provided for moving the cutting tool along the first support member so that cutting of sheet material, disposed on the support surface, along the line parallel to the first support member is effected.
Additionally, it is preferred that a second elongated support member be provided with a second cutting tool mounted thereon, the second support member being linearly movable with respect to the first and second guide members along the first and second guide members, and the cutting tool being movable along the second support member so that cutting of sheet material, disposed on the support surface, along the line parallel to the second support member is effected. The guide members also are preferably mounted so that they are movable with respect to each other, always being disposed in a parallel relationship. Such a movement can be effected by providing a pair of lead screws, traveling nuts associated with one of the guide members and each lead screw, and a hand crank arrangement or the like for rotating both of the lead screws at the same time.
Power means may be provided for moving the cutting tool along the support members, such as an electric motor and a pinion driven by the motor, which pinion engages a rack on the support member. Alternatively, a simple handle may be provided on the cutter tool and the handle grasped to move the tool, or a rope or the like attached to the handle to pull it along a desired path. The cutting tool preferably will comprise a cutting wheel, and the wheel may either effect cutting as it is moved along the insulation, or the wheel can be powered. In the normal situation, the wheel would effect cutting just as it is moved along the material to be cut, and in this way could be a wheel such as shown in U.S. Pat. No. 4,050,336.
In adjusting the support members with respect to the guide members, locking screws or the like are released to allow linear movement of the support members with respect to the pivotal mounting means, and the pivotal mounting means with respect to the guide members, so that any angular orientation may be provided between the support members and between the support members and the guide members.
If desired, the cutting wheels could be mounted so that they may also assume a 90.degree. orientation with respect to the support members, and in this case would be mounted generally as shown in FIG. 3b of U.S. Pat. No. 4,050,336.
It is the primary object of the present invention to provide semi-automatic cutting apparatus for quickly and easily cutting a wide variety of polygon shapes from sheet material, especially cutting insulation for lining transition duct work pieces. This and other objects of the invention will become clear from an inspection and the detailed description of the invention, and from the appended claims.